An optical data reading apparatus, e.g., a CD-ROM (Compact Disc type Read Only Memory) system, has been used in data processing systems, such as computers or word processors, as an external data memory system. In the CD-ROM system, a CD-ROM optically stores data. The data stored in the CD-ROM is read by the CD-ROM system and then supplied to the computers, the word processors and the like. The data stored in the CD-ROM is read by the CD-ROM system without mechanical contact to the CD-ROM.
Thus, the CD-ROM system has a short access time to access desired data, similar to the access time of conventional magnetic memory discs such as floppy discs. The CD-ROM system has a higher durability in comparison to the magnetic memory discs. Due to the above advantages, the CD-ROM system has been used in many fields, e.g., video image memories, data memories of CAD/CAM systems, data memories of electronic publishing systems, etc. in addition to computers and word processors.
Optical discs, e.g., the CD-ROMS, are broadly classified, according to the type of data recording and/or reproduction, into a reflection pit type, a phase shift type, and an optical/magnetic transducing type. However, in all the types a reflection light given from the optical discs is applied to an optical pickup head provided in the optical data reading apparatus. The reflection light is photoelectrically converted into an electrical signal. The electrical signal is suitably processed by a signal processing section in the optical data reading apparatus.
If the optical pickup head is covered with dust, the reflection light applied to the optical pickup head decreases so that the electrical signal output from the optical data reading apparatus also decreases. This causes errors or makes difficult the access operation of the optical discs, causing the optical data reading apparatus to work incorrectly. Such a problem may be caused by dust contained in the environmental air which is taken into the optical data reading apparatus. The dust gradually covers the optical pickup head. This problem occurs very often if the optical data reading apparatus is provided with a forced air ventilated cooling system.
To solve the problem, a user or an operator of the optical data reading apparatus must clean the optical pickup head. However, it is difficult for the operator to distinguish whether the problem is caused by dust or by other causes because many other causes as well as dust raise similar problems, e.g., the errors and the difficulty of accessing desired data. Therefore, the operator must try many possible solutions solving a problem, including cleaning the optical pickup head. However, cleaning is futile if the problem is not caused by dust on the optical pickup head. Further, frequent and unnecessary cleanings may injure the optical pickup head.